Relationship of intelligence with cognitive therapy outcome.

Theorists have speculated that intelligence is positively associated with the capacity to benefit from cognitive-behavioral therapies. We evaluated this notion by relating pre-treatment measures of fluid and crystallized intelligence to self-reported symptom reduction in a naturalistic study (n = 106) of cognitive therapy for outpatients with principal diagnoses of major depression, dysthymia, or generalized anxiety disorder. Intelligence measures did not significantly predict outcome, and nonsignificant relationships were in the opposite direction from the theoretical prediction. Discussion centered on possible limitations to the generalizability of these results and on the logical interpretation of prediction studies in psychotherapy research.